Moss grows in many undesirable areas including lawns, golf course putting greens, other landscaped areas, and on structures such as walls, building foundations, monuments, and the like. Moss growing on structures is relatively easy to control using harsh chemicals, but moss is particularly hard to control or eradicate is areas that also contain desirable plants such as grasses. As a result, moss is especially a growing concern among homeowners, professional landscapers, and golf course superintendents.
Moss growing amongst grass and other desirable plants is a major concern for a number of reasons. Foremost among these is that moss detracts from the attractiveness of well-maintained lawns and other landscaped areas. Moss also tends to retain moisture and can decrease the usefulness of a lawn area. Additionally, under certain conditions, moss tends to spread easily and will crowd out other desirable plants, especially grasses.
Moss is a photosynthesizing terrestrial plant. Mosses are non-vascular plants so they need to be in contact with water to avoid drying out. Many mosses absorb water over their entire surface area and they are generally adapted to shady, moist locations. However, some mosses can survive long periods of desiccation (sometimes several years) and can withstand high temperatures in a dormant state. Laboratory studies have shown that mosses can tolerate dehydration levels equal to 80% of original biomass. When mosses are rehydrated, an immediate respiratory burst occurs, but recovery is slow.
While we have used the term “moss” in a generic sense, it has been reported that thousands of species of mosses exist. Moss can develop and thrive in many different environments, but areas that have poor soil conditions, lots of shade, and are damp tend to be the best for moss growth. Many of the moss varieties are known to infest home lawns, but the types that are known to infest golf course putting greens are more limited in number. In particular, it has been found that there are four moss varieties that often inhabit golf course putting green turf. They are Byrum argentums, Byrum lisae, Amblystegium trichopodium, and Brachythecium spp (Happ, K., USGA Green Section Record, September 1998). Byrum argentum (or silvery thread moss) is found in open sites and is one of the most common contaminants of putting green turf. It can generally be easily distinguished from other mosses because of its silvery appearance.
The presence of moss on putting greens is a special problem because of the unique conditions found in these areas. Golf course superintendents are faced with many turf management decisions, most of which are centered on providing the best possible playing conditions. This usually involves mowing the putting green grass (typically a short growing bentgrass variety) as short as reasonably possible. The shorter the putting green grass is, the faster the ball tends to travel. Faster putting surfaces tend to be the most desirable among golfers. Consequently, the health of putting green turf is compromised in order to deliver the desired playing effect.
Seeking maximum surface performance by cutting the greens short can lead to reduced bentgrass vigor. The shorter the greens are cut and the lower the bentgrass vigor, the better the conditions are for moss development and growth. A small moss colony can proliferated and turn into a bigger problem that is more difficult to overcome. One reason that moss on bentgrass putting greens proliferates is because of re-infestation by golfers and greens maintenance equipment that inadvertently carry the spores to new locations. If conditions remain favorable for moss growth, the moss can spread across a putting surface and severely lower playing conditions. The challenge for golf course superintendents is to eliminate moss infestation without compromising the health of putting green surfaces.
Despite these problems, the solutions for controlling or eradicating moss from lawns, golf course putting greens, and similar areas has remained rather limited and unsatisfactory. A few products exist that have been used to control moss to some extent, but to our knowledge, there are no commercially available products that effectively kill moss over a broad area without damaging the turf. These products are typically powdered forms of certain metallic salts such as iron, zinc, and copper-sulfur compounds. They provide varying degrees of success, but also have significant drawbacks. Such powdered compositions are generally used only for spot treatment as they are difficult to apply over a broad area. While they can sometimes be put into solution, the concentration required to kill the moss colonies tends to be harmful to the grass. Additionally, we know of a liquid product called DeMoss™ sold by Mycogen Corporation that is advertised as a moss control product. This product is a potassium salt of fatty acid.
In addition to the known commercial products several inventors in the patent literature have created methods to control moss in lawns and on structures. Some examples of these methods are briefly discussed below.
U.S. Pat. No. 5,139,561 to R. Talbot and K. Cooper discloses a method for protecting growing plants, including grasses, from fungal or microbial pathogens using a composition containing tetrakis (hydroxymethyl) phosphonium salt. One particular application of the composition is for control of mosses in lawns.
U.S. Pat. No. 4,276,732 to J. Nielsen discloses a device for killing moss on rooftops. In one embodiment, the device comprises a trough made of a layer of lead and copper. As rainwater filters through holes in the trough, an electrolytic action occurs in which ions of the metals dissolve into the water. The resultant aqueous electrolyte kills moss growing on the roof.
U.S. Pat. No. 5,009,700 to Rothgery describes a process for ridding moss from unwanted locations such as lawns, walls, monuments, building foundations, tombstones, and the like. The process comprises contacting the moss growing in said unwanted locations with an effective amount of a pyrithione salt. The composition optionally includes a surfactant or wetting agent.
U.S. Pat. No. 5,108,481 to T. Shutt discloses a method of making a pelletized ferrous sulfate. It is further disclosed that the pelletized ferrous sulfate may be used as a moss-control agent.
U.S. Pat. No. 3,964,893 to J. Everingham and K. Hoenke teaches a lawn moss control composition comprising a granular ferric ammonium sulfate-ammonium sulfate double salt. The patent further discloses that the ferric double salt is as effective as ferrous ammonium sulfate for promoting the greening of turf grass.
U.S. Pat. No. 5,589,229 to R. Howard discloses a composition and method for preventing moss growth on roofs. The composition is an aqueous solution containing sodium oxide, silicon dioxide and a surfactant that is sprayed on the surface to be protected from moss growth.
U.S. Pat. No. 4,936,898 to J. Nielsen discloses a method for killing moss growing on a surface by using a moss-killing powder containing an atomized elemental metal which slowly dissolves with water to form a biocidal solution which kills the moss. The powder is essentially a mixture of elemental zinc and copper mixed with a powdered carrier such as silica clay.
In addition to these commercial and patented chemical methods, manual methods of moss removal from grass is commonly used. For example, a non-chemical method for the control of moss in lawns is to rake out the moss, fertilize the ground, and re-seed with grass. This raking method is time consuming and hard on the grass. This method and other manual methods of moss removal can not be accomplished without also damaging the lawn. Accordingly, it would be desirable to provide a simpler moss treatment method that selectively eradicates moss in a lawn, golf course putting green, or other area, without harming the co-located grasses.
None of the known commercial products or the products described in the patent literature and discussed above are fully satisfactory in meeting the current needs of homeowners, professional landscapers, and golf course superintendents. The present inventors have discovered a composition that more fully meets those needs by providing a convenient and effective moss control composition that does not damage grasses.